Hi FunkMeister,

For one plant you should be fine with running all those CFL's. I am on my first grow and am using 18 -23 and 26watt bulbs and am getting buds. I might not yield as much as I could if using a HPS but I am still getting a lot of buds. When I vegged I used 12-26 watt 6500k, now in flowering I am using 12-23 watt 2700k and 6-26 watt 6500k bulbs. In regards to the 250 watt hps, it will put out more lumens then your CFL's, thus more usable light with less power.
My suggestion, grow it out with the cfl's if your new to growing, get used to it, see if ya want to keep growing all the time, if you do (i am sure you will), then invest in a equivalent hps and change all the light bulbs in the house to your leftover cfl's(win win situation right). Your almost at the 400 watt marker with your cfl's, a 400 watt hps puts out 50,000 lumens, compare that with the 28,000 est. lumens from 400watts of cfl's, its almost double the light output!